In recent years, various user interface systems have been proposed. In a certain user interface system among the proposed user interface systems, groups including letters of the alphabets, numbers and commands are registered, and these groups are divided into subgroups. Each of the subgroups is associated with a portion of a finger of a user. Also, the user interface system comprises a keypad including a plurality of keys, and at least one of the letters of the alphabets, numbers and commands is assigned to each of the plurality of keys. Furthermore, the user interface system comprises a finger recognition system. The finger recognition system recognizes a finder contacting a key, and selects one of the subgroups assigned to the finger interacting with the key.
[Patent document 1] Japanese Unexamined Patent Publication No. 2003-529130